using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Collections.Generic;
using System.Diagnostics;
using System.Numerics;
using Enu = System.Linq.Enumerable;

class Program
{

    public void Solve()
    {
        int[] R = new int[3], M = new int[3];
        for (int i = 0; i < 3; i++)
        {
            R[i] = Reader.Int();
            M[i] = Reader.Int();
        }
        long ans = Get(R, M);
        Console.WriteLine(ans);
    }

    private static long Get(int[] R, int[] M)
    {
        long X = (R[0] > 0) ? R[0] : M[0];
        long lcm = LCM(M[0], M[1]);
        long to = lcm + M[0];
        while (X <= to && X % M[1] != R[1]) X += M[0];
        if (X % M[1] != R[1]) return -1;

        to = LCM(lcm, M[2]) + lcm;
        while (X <= to && X % M[2] != R[2]) X += lcm;
        if (X % M[2] != R[2]) return -1;
        return X;
    }

    static long GCD(long a, long b) { while (b != 0) { long r = a % b; a = b; b = r; } return a; }
    static long LCM(long a, long b) { return a / GCD(a, b) * b; }
}


class Entry { static void Main() { new Program().Solve(); } }
class Reader
{
    private static TextReader reader = Console.In;
    private static readonly char[] separator = { ' ' };
    private static readonly StringSplitOptions op = StringSplitOptions.RemoveEmptyEntries;
    private static string[] A = new string[0];
    private static int i;
    private static void Init() { A = new string[0]; }
    public static void Set(TextReader r) { reader = r; Init(); }
    public static void Set(string file) { reader = new StreamReader(file); Init(); }
    public static bool HasNext() { return CheckNext(); }
    public static string String() { return Next(); }
    public static int Int() { return int.Parse(Next()); }
    public static long Long() { return long.Parse(Next()); }
    public static double Double() { return double.Parse(Next()); }
    public static int[] IntLine() { return Array.ConvertAll(Split(Line()), int.Parse); }
    public static int[] IntArray(int N) { return Enu.Range(0, N).Select(i => Int()).ToArray(); }
    public static int[][] IntTable(int H) { return Enu.Range(0, H).Select(i => IntLine()).ToArray(); }
    public static string[] StringArray(int N) { return Enu.Range(0, N).Select(i => Line()).ToArray(); }
    public static string Line() { return reader.ReadLine().Trim(); }
    private static string[] Split(string s) { return s.Split(separator, op); }
    private static string Next() { CheckNext(); return A[i++]; }
    private static bool CheckNext()
    {
        if (i < A.Length) return true;
        string line = reader.ReadLine();
        if (line == null) return false;
        if (line == "") return CheckNext();
        A = Split(line);
        i = 0;
        return true;
    }
}